I agree, it seems crazy to buy now. But will we actually see a crash, or just a period of stagnation?
If property values goes up faster than salary per home, you'll end up with a precarious housing market subject to the whims of investor sentiment. Workers won't be able to move in and back up the house valuation if they are priced too high.
A few places along the peninsula had stagnant or slowly rising property values, like Palo Alto. Values in SF either held or declined very little. Places like Oakland lost a little value and Hayward, maybe one of the least desirable areas around the bay regained all of its lost value in just a few years.
From Jan 1987 to Jan 2018, prices in San Francisco MSA have gone up 5.0% a year, ((258.81-46.95)/46.95)^(1/(2018-1987)). The equivalent amount invested in the stocks over that time period would have yielded 10.3% a year[1], with dividends reinvested.
Unless you are planning to use it as an investment property and reinvest rents (net of property tax, maintenance) in other properties, it still doesn't appear clear that buying a home vs renting and investing heavily in the market is a better bet, not to mention other intangibles like upkeep and longer commutes.